| Abstrak/Abstract |
We have carried out the density functional theory calculations of vacancies in monolayer h-BN. We model five configurations, two configurations of monovacancies ( and ) and three configurations (, , and ) of divacancies. In the case of monovacancies, we find that and form a C3V symmetry. In the divacancy case, we find that produces a heart-like configuration having two pentagons and leaving two dangling bonds, while leaves four dangling bonds. As for , it produces two pentagons and has no dangling bond. The calculated formation energies of , and are 11.65?eV, 12.05?eV, 17.59?eV, 22.32?eV, and 16.89?eV, respectively. These energies show that is more stable than , while is more stable than . We conclude that the N-rich h-BN sheet is energetically more favorable to be formed rather than the B-rich one. However, the most stable configuration of the divacancies belongs to compensating from the absence of the dangling bond, which obeys the dangling-bond-counting-model. Furthermore, we calculate band structures of the most stable mono- and divacancies. We find that monovacancy somewhat changes the electronic structure, shown by localized states near the Fermi level, while the divacancy produces two new states above the Fermi level. |
